In broadcast networks, content is made available to multiple users, typically in synchronous fashion, without being specifically addressed to individual user nodes in point-to-point fashion. Examples of broadcast networks include cable and satellite television networks, satellite radio networks, IP networks used for multicasting content and networks used for podcasts or telephony broadcasts/multicasts. Content may also be broadcast over the airwaves. Because content is broadcast in these networks, the network operator generally does not know (based on content transmissions) the size or composition of the audience for particular content.
For a number of reasons, it may be desired to estimate the size and composition of an audience on a content segment specific basis. This information may be of interest to programming content providers and network operators in understanding and evaluating their performance in providing a product of interest. More pragmatically, this information is of interest to asset providers such as advertisers who provide assets for dissemination via the broadcast network, typically on a paid basis. Such asset providers generally contract with programming providers or network operators for dissemination of assets with payment based on the size and composition of the expected audience. Accordingly, audience measurement information is important in instilling confidence among asset providers that they will receive sufficient return on their investments and in verifying that billing rates are appropriate.
A number of different audience measurement techniques have been employed including audience surveys and monitoring sample groups. For example, telephone surveys may be conducted in which network users are identified and questioned regarding broadcast network usage. However, this is labor intensive, intrusive with respect to the network users and requires considerable surveying expertise to obtain information that reliably represents usage patterns of the wider audience. Moreover, while users' recollections concerning general usage patterns may tend to be reasonably accurate, recollections regarding particular content segments on particular occasions are questionable.
Monitoring of sampling groups generally involves placing monitoring dedicated equipment at the premises of network users to eavesdrop on broadcast network usage by the user household and reporting that information back to a monitoring system. For example, in the context of television networks including cable television networks, ratings information is generated by the Nielsen Media Research Corporation. In on implementation, Nielsen system involves receiving information regarding which programs were viewed by each household of a sampling group and correlating that information to known demographic information for that household. This information is then used to generate overall ratings for programs as well as ratings with respect to individual demographics groups. That information forms the basis of pricing for advertising contracts for particular advertising time slots associated with particular programs.